The physics of chromatin

Helmut Schiessel

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arXiv · cond-mat/0303455

The physics of chromatin

Helmut Schiessel

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Abstract

Recent progress has been made in the understanding of the physical properties of chromatin -- the dense complex of DNA and histone proteins that occupies the nuclei of plant and animal cells. Here I will focus on the two lowest levels of the hierarchy of DNA folding into the chromatin complex: (i) the nucleosome, the chromatin repeating unit consisting of a globular aggregate of eight histone proteins with the DNA wrapped around: its overcharging, the DNA unwrapping transition, the ''sliding'' of the octamer along the DNA. (ii) The 30nm chromatin fiber, the necklace-like structure of nucleosomes connected via linker DNA: its geometry, its mechanical properties under stretching and its response to changing ionic conditions. I will stress that chromatin combines two seemingly contradictory features: (1) high compaction of DNA within the nuclear envelope and at the same time (2) accessibility to genes, promoter regions and gene regulatory sequences.

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Helmut Schiessel. 2003-03-21. The physics of chromatin. https://arxiv.org/abs/cond-mat/0303455

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